Preparation of (R)- and (S)-N-protected 3-hydroxypyrrolidines by hydroxylation with Sphingomonas sp. HXN-200, a highly active, regio- and stereoselective, and easy to handle biocatalyst

Hydroxylation of N-benzylpyrrolidine 8 with resting cells of Sphingomonas sp. HXN-200 gave N-benzyl-3-hydroxypyrrolidine 15 in 53% ee (S) with an activity of 5.8 U/g CDW. By changing the "docking/protecting group" in pyrrolidines, hydroxylation activity and enantioselectivity were further improved and the enantiocomplementary formation of 3-hydroxypyrrolidines was achieved: hydroxylation of N-benzoyl-, N-benzyloxycarbonyl-, N-phenoxycarbonyl-, and N-tert-butoxycarbonyl-pyrrolidines 9-12 gave the corresponding 3-hydroxypyrrolidines 16-19 in ee of 52% (R), 75% (R), 39% (S), and 23% (R), respectively, with an activity of 2.2, 16, 14, and 24 U/g CDW, respectively. Simple crystallizations increased the ee of 16-18 to 95% (R), 98% (R), and 96% (S), respectively. Hydroxylation of pyrrolidines 8-12 with soluble cell-free extracts of Sphingomonas sp. HXN-200 and equimolar NADH gave 3-hydroxypyrrolidines 15-19 in nearly the same ee as the products generated by whole cell transformation, suggesting that this strain possesses a novel soluble alkane monooxygenase. Cells of Sphingomonas sp. HXN-200 were produced in large amounts and could be stored at -80 degrees C for 2 years without significant loss of activity. The frozen cells can be thawed and resuspended for biohydroxylation, providing a highly active and easy to handle biocatalyst for the regio- and stereoselective hydroxylation of nonactivated carbon atoms. These cells were used to prepare 1.0-3.2 g (66.4-93.5% yield) of 3-hydroxypyrrolidines 16-19 by hydroxylation of pyrrolidines 9-12 on 0.9-2 L scale. Preparative hydroxylation was also achieved with growing cells as biocatalysts; hydroxylation of pyrrolidine 11 on 1 L scale gave 1.970 g (79.7% yield) of 3-hydroxypyrrolidine 18.

Geometric CP violation with extra dimensions

We discuss how CP symmetry can be broken geometrically through orbifold projections in hidden extra dimensions in the context of brane-bulk models for particle unifications. The CP violation arises from a crash between the geometry of the compactification and the original higher dimensional CP definition. We present toy models to illustrate the idea and suggest ways to incorporate it into more realistic models.

Increased antiviral and opsonic activity of a highly multimerized collectin chimera

Altering the carbohydrate binding properties of surfactant protein D (SP-D) [e.g., by replacing its carbohydrate recognition domain (CRD) with that of either mannose binding lectin (MBL) or conglutinin] can increase its activity against influenza A virus (IAV). The current study demonstrates that the degree of multimerization of SP-D is another independent determinant of antiviral activity. A chimeric collectin containing the N-terminus and collagen domain of human SP-D and the CRD of MBL formed high-molecular-weight multimers similar to those previously described for human SP-D. Using several complementary assays, and diverse viral strains, the chimeric multimers showed greater anti-IAV activity than similarly multimerized preparations of SP-D or incompletely oligomerized preparations of the chimera. More highly multimerized preparations of the chimera also caused greater increases in uptake of IAV by neutrophils. These studies may have implications for development of collectins as therapeutic agents and understanding of natural variations in susceptibility to IAV infection.

Analysis of minimal sequences on JC virus VP1 required for capsid assembly

Human JC virus (JCV) belongs to the family of Polyomaviridae. The viral capsid is composed of 72 capsomeres. Five VP1 molecules make up a capsomere structure. To investigate the minimal sequences on JCV VP1 polypeptide required for capsid assembly, the first 12 (Delta N12) and 19 (Delta N19) amino acids at the N-terminus and the last 16 (Delta C16), 17 (Delta C17), and 31 (Delta C31) amino acids at the C-terminus of VP1 were truncated and expressed in E. coli. The VP1 proteins of Delta N12 and Delta C16 were able to self-assemble into a virus-like particle similar to that of wild-type (WT) VP1. However, the mutant proteins of Delta N19, Delta C17, and Delta C31 formed a pentameric capsomere structure as demonstrated by a 10-50% sucrose gradient centrifugation and electron microscopy. These results suggest that the 12 amino-terminal and 16 carboxy-terminal amino acids of VP1 are dispensable for the formation of virus-like particles, and further truncation at either end of VP1 leads to the loss of this property.

Disulfide bonds stabilize JC virus capsid-like structure by protecting calcium ions from chelation

To investigate the role of disulfide bonds in the capsid structure, a recombinant JC virus-like particle (VLP) was used. The major capsid protein, VP1, of the JC virus was expressed in yeast cells. The yeast-expressed VP1 was self-assembled into a VLP. Disulfide bonds were found in the VLP which caused dimeric and trimeric VP1 linkages as demonstrated by non-reducing SDS-PAGE. The VLP remained intact when disulfide bonds were reduced by dithiothreitol. The VLP without disulfide bonds could be disassembled into capsomeres by EGTA alone, but those with disulfide bonds could not be disassembled by EGTA. Capsomeres were reassembled into VLPs in the presence of calcium ions. Capsomeres formed irregular aggregations instead of VLPs when treated with diamide to reconstitute the disulfide bonds. These results indicate that disulfide bonds play an important role in maintaining the integrity of the JC VLP by protecting calcium ions from chelation.

Identification of a DNA encapsidation sequence for human polyomavirus pseudovirion formation

Human polyomavirus is a naked capsid virus containing a closed circular double-stranded DNA genome. The mechanism of DNA encapsidation for the viral progeny formation is not fully understood. In this study, DNA encapsidation domain of the major capsid protein, VP1, of the human polyomavirus JCV was investigated. When the first 12 amino acids were deleted, the E. coli expressed VP1 (Delta N12VP1) failed to encapsidate the host DNA although the integrity of the capsid-like structure was maintained. In addition, capsid-like particles of Delta N12VP1 did not package exogenous DNA in vitro, which is in contrast to that of the full-length VP1 protein. These findings suggest that the N-terminal of the first 12 amino acids of VP1 were responsible for DNA encapsidation. The importance of amino acids in the DNA encapsidation domain was determined further using site-directed mutagenesis. All of the positively charged amino acids at the N-terminal region of VP1 were essential for DNA encapsidation. The results indicate that the N-terminal region of the human polyomavirus major capsid protein VP1 may be involved in viral genome encapsidation during progeny maturation.

Muristerone A-induced nerve growth factor release from genetically engineered human dermal fibroblasts for peripheral nerve tissue engineering

In this study, human dermal fibroblasts (hDFBs) were genetically modified to release human nerve growth factor (NGF) using an ecdysone-inducible system. NGF cDNA was inserted into the pIND vector and then hDFBs were cotransfected with pIND-NGF and pVgRXR. Muristerone A, an analog of ecdysone, was used as the inducing agent. NGF release from transfected hDFBs was assessed in vitro and in vivo. Transfected hDFBs in the presence of Muristerone A possessed a maximal in vitro release of 8.5 +/- 0.4 pg of NGF/mL per 10(3) cells, demonstrating significantly higher NGF levels compared to control hDFBs. The in vitro release rate curve for transfected hDFBs in the presence of Muristerone A exhibited a maximum of 5.1 +/- 0.2 ng NGF/10(6) cells/day. A PC-12 bioassay demonstrated that the in vitro NGF released is bioactive. When transfected hDFBs in the presence of Muristerone A were placed in vivo in nude rats, NGF levels reach 2074 +/- 257 pg/mL and 1620 +/- 132 pg/mL at 24 and 48 h, respectively. These levels were significantly higher than negative control and wound fluid levels. Results support further in vivo investigation of this molecular "on" switch for peripheral nerve regeneration.

Thrombolytic therapy: what is its role in free flap salvage?

Thrombolytic agents have been demonstrated to improve free flap salvage in animal models. However, clinical evidence regarding their efficacy has been scant. The authors reviewed their experience with flap salvage using thrombolytic therapy in 1,733 free flaps from February 1990 to July 1998. Patients with intraoperative pedicle thrombosis were excluded from this review. Forty-one of the 55 free flaps that were reexplored emergently were identified as having pedicle thrombosis. Of these 41 flaps, 28 free flaps were salvaged (flap salvage group, 68%) and 13 free flaps failed (flap failure group, 32%). Thrombolytic therapy (urokinase in 7 patients, tissue plasminogen activator in 1 patient) was used in six flaps in the flap salvage group and two flaps in the flap failure group. Statistical analysis demonstrated no difference between the two groups with regard to thrombolytic therapy. There was also no difference between the two groups with regard to use of systemic heparin (100-500 U per hour) at the time of pedicle thrombosis or with regard to whether Fogarty catheters were used. Smoking, preoperative radiotherapy, and the use of interpositional vein grafts during initial flap reconstruction had no impact on the outcome of flap salvage. The flap salvage group was reexplored at a mean of 1.5 days compared with the flap failure group, which was reexplored at a mean of 4.2 days (p = 0.007). Early detection of pedicle thrombosis remains the most important factor in the salvage of free flaps. Although these numbers are small and definitive statements cannot be made, the role of thrombolytic agents in free flap salvage requires further clinical evaluation.

A regulatory region rearranged BK virus is associated with tubulointerstitial nephritis in a rejected renal allograft

A renal allograft transplant patient with high serum creatinine presented clinical symptoms of rejection. Sections of renal biopsy tissue showed mononuclear leukocyte infiltration in the tubulointerstitium and nuclear enlargement with inclusions in the tubular epithelium. The morphological characteristics resembled polyomavirus-induced interstitial nephritis. Electron microscopy of the nuclear inclusions showed paracrystalline arrays of naked viral particles with a diameter of 45 nm. Molecular studies revealed that a new variant of BK virus (BKV) with rearrangement at the regulatory region was involved in the nephritis. The BKV regulatory region contained a tandem repeat from the P-block to the Q-block causing duplication of several important transcriptional elements or transcriptional factor binding motifs. This is the first report to show a naturally occurring BKV variant with regulatory region rearrangement associated with tubulointerstitial nephritis.

A novel chordin-like protein inhibitor for bone morphogenetic proteins expressed preferentially in mesenchymal cell lineages

Chordin is a bone morphogenetic protein (BMP) inhibitor that has been identified as a factor dorsalizing the Xenopus embryo. A novel secreted protein, CHL (for chordin-like), with significant homology to chordin, was isolated from mouse bone marrow stromal cells. Injection of CHL RNA into Xenopus embryos induced a secondary axis. Recombinant CHL protein inhibited the BMP4-dependent differentiation of embryonic stem cells in vitro and interacted directly with BMPs, similar to chordin. However, CHL also weakly bound to TGFbetas. In situ hybridization revealed that the mouse CHL gene, located on the X chromosome, was expressed predominantly in mesenchyme-derived cell types: (1) the dermatome and limb bud mesenchyme and, later, the subdermal mesenchyme and the chondrocytes of the developing skeleton during embryogenesis and (2) a layer of fibroblasts/connective tissue cells in the gastrointestinal tract, the thick straight segments of kidney tubules, and the marrow stromal cells in adults. An exception was expression in the neural cells of the olfactory bulb and cerebellum. Interestingly, the spatiotemporal expression patterns of CHL were distinct from those of chordin in many areas examined. Thus, CHL may serve as an important BMP regulator for differentiating mesenchymal cells, especially during skeletogenesis, and for developing specific neurons.

Application of pulsed Doppler ultrasound for the evaluation of small intestinal motility in dogs

The purpose of this study was to verify whether small intestinal peristalsis could be observed and quantitatively assessed using pulsed-Doppler ultrasound. Pulsed-Doppler ultrasound was used to evaluate small intestinal peristalsis after a meal in ten normal dogs and ten sedated dogs. The small intestinal peristalses were measured 0, 1, 3, 6, 9, 12, and 24 hours after a 24-hour fast and after feeding. The number of small intestinal peristalsis were 0.133/min, 0.100/min, 0.033/min, 0.167/min, 0.070/min, 0.067/min, and 0.100/min in the fasted dogs, and 1.667/ min, 0.933/min, 1.133/min, 1.234/min, 1.933/min, 1.533/ min, and 0.533/min in fed dogs, respectively. In the dogs sedated with xylazine HCl, the number of small intestinal peristalsis was significantly reduced (p<0.01). However, in the dogs treated with ketamine HCl and acepromazine, the number of small intestinal peristalsis remained unchanged. Therefore, it can be concluded that pulsed-Doppler ultrasound allows graphic visualization of the intestinal movements, which can be subjected to qualitative and quantitative analysis, and may be suitable for a non-invasive study of small intestinal motility.

Effect of dopamine on excretory urographic image quality and the prevention of contrast-induced nephropathy in dogs

The effect of low dose dopamine on the excretory urographic image quality and contrast media-induced nephropathy in normal dogs (experiment 1) and the dogs with decreased renal function (experiment 2) were assessed. In experiment 2, decreased renal function was induced by gentamicin overdose. In each experiment, animals were divided into 3 groups. In group 1, only contrast medium (iohexol) was administered. In group 2, contrast medium plus intravenous fluid (0.9% saline) were administered. And in group 3, contrast medium plus intravenous fluid and low dose dopamine were administered. Investigated parameters included intrarenal resistive index (RI), serum BUN and creatinine concentrations, contrast medium elimination time and radiographic image quality. In experiment 1, RI of group I increased at 80 min after contrast medium administration (p<0.05), but RI of group 3 decreased at 48 and 72 hr (p<0.05). Serum BUN concentration of group 1 was higher than that of group 2 and 3 (p<0.05); in radiographic examination, contrast medium elimination time decreased in group 2 and 3, but image quality of group 2 was inferior to that of group 3. In experiment 2, image quality of group 3 only provided adequate visualization of renal structures. The formula of contrast medium plus low dose dopamine was found to provide good nephrogram and pyelogram image quality without supplemental contrast medium, and to protect renal tubules from prolonged exposure to concentrated contrast medium.

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis

OBJECTIVE

The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy.

METHODS

The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured.

RESULTS

Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three.

CONCLUSIONS

Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Birth defects after maternal exposure to corticosteroids: prospective cohort study and meta-analysis of epidemiological studies

BACKGROUND

Corticosteroids are first-line drugs for the treatment of a variety of conditions in women of childbearing age. Information regarding human pregnancy outcome with corticosteroids is limited.

METHODS

We collected prospectively and followed up 184 women exposed to prednisone in pregnancy and 188 pregnant women who were counseled by Motherisk for nonteratogenic exposure. The primary outcome was the rate of major birth defects. A meta-analysis of all epidemiological studies was conducted. The Mantel-Haenszel summary odds ratio was calculated for the pooled studies with 95% confidence intervals. A cumulative summary odds ratio was also calculated by combining studies in chronological order. Chi-squared for homogeneity was determined to establish the comparability of the studies.

RESULTS

In our prospective study, there was no statistical difference in the rate of major anomalies between the corticosteroid-exposed and control groups. In the meta-analysis, the Mantel-Haenszel summary odds ratio for major malformations with all cohort studies was 1.45 [95% CI 0.80, 2.60] and 3.03 [95% CI 1.08, 8. 54] when Heinonen et al. ('77) was removed. This suggests a marginally increased risk of major malformations after first-trimester exposure to corticosteroids. In addition, summary odds ratio for case-control studies examining oral clefts was significant (3.35 [95% CI 1.97, 5.69]).

CONCLUSIONS

Although prednisone does not represent a major teratogenic risk in humans at therapeutic doses, it does increase by an order of 3.4-fold the risk of oral cleft, which is consistent with the existing animal studies.

Performance characterization of anaerobic sequencing batch reactor process for digestion of night soil

Laboratory experiments were conducted to investigate the performance of an anaerobic sequencing batch reactor (ASBR) process for night soil treatment. Performances of the reactors were evaluated at an equivalent hydraulic retention time (HRT) of 10 days with an equivalent loading rate of 2.6 kgVS/m3/d (3.1 kgCOD/m3/day) at 35 degrees C. Digestion of a night soil was possible using the ASBR at an HRT of 10 days in spite of high concentration of ammonia nitrogen and settleable solids. Solids were accumulated rapidly in the ASBRs, and their concentrations were 2.3-2.4 times higher than that in a completely mixed control reactor. Remarkable increases in gas production were observed in the ASBRs compared with the control reactor. Average increases in equivalent daily gas production from the ASBRs were 205-220% compared with that from the control run. The ASBR with reaction period/thickening period ratio (R/T ratio) of 1 showed a little higher gas production and organic removal efficiency than that with R/T ratio of 3. Volatile solids removals based on supernatant of the ASBRs were 12-14% higher than that of the control reactor. Thus, the ASBR was a stable and effective process for the treatment of night soil having high concentration of settleable organics and ammonia nitrogen.

Surfactant protein D enhances phagocytosis and killing of unencapsulated phase variants of Klebsiella pneumoniae

Pulmonary surfactant protein D (SP-D) is a collagenous C-type lectin (collectin) that is secreted into the alveoli and distal airways of the lung. We have studied the interactions of SP-D and alveolar macrophages with Klebsiella pneumoniae, a common cause of nosocomial pneumonia. SP-D does not agglutinate encapsulated K. pneumoniae but selectively agglutinates spontaneous, unencapsulated phase variants, such as Klebsiella strain K50-3OF, through interactions with their lipopolysaccharides (LPS). These effects are calcium dependent and inhibited with maltose but not lactose, consistent with involvement of the SP-D carbohydrate recognition domain. Precoating of K50-3OF with SP-D enhances the phagocytosis and killing of these organisms by rat alveolar macrophages in cell culture and stimulates the production of nitric oxide by the NR-8383 rat alveolar macrophage cell line. SP-D similarly enhances the NO response to K50-3OF LPS adsorbed to Latex beads under conditions where soluble LPS or SP-D, or soluble complexes of SP-D and LPS, do not stimulate NO production. Our studies demonstrate that interactions of SP-D with exposed arrays of Klebsiella LPS on a particulate surface can enhance the host defense activities of alveolar macrophages and suggest that activation of macrophages by SP-D requires binding to microorganisms or other particulate ligands. Because unencapsulated phase variants are likely to be responsible for the initial stages of tissue invasion and infection, we speculate that SP-D-mediated agglutination and/or opsonization of K. pneumoniae is an important defense mechanism for this respiratory pathogen in otherwise healthy individuals.

Apoptosis of ventricular and atrial myocytes from pacing-induced canine heart failure

OBJECTIVE

Rapid ventricular pacing in dogs results in a low output cardiomyopathic state similar to idiopathic dilated cardiomyopathy in man. Cell death by apoptosis may play an important role in the loss of cardiac function. This study investigates the molecular pathways involved in the regulation of apoptosis in dogs with pacing-induced heart failure.

METHODS

Apoptosis was identified by terminal transferase nick end-labelling (TUNEL) in the ventricles and atria of dog hearts affected by rapid-ventricular pacing. Western blots were used to determine expression of the components involved in the initiation (Fas, Fas-Ligand, FADD), regulation (Bcl-2, Bax) and execution (caspase-2 and caspase-3) of apoptosis.

RESULTS

Pacing-induced heart failure resulted in a significant increase in the number of ventricular and atrial myocyte nuclei undergoing apoptosis as measured by TUNEL. Compared to the samples from control hearts (n=6) the expression of Bcl-2, an inhibitor of apoptosis, was significantly reduced in ventricles from five dogs with pacing-induced heart failure. No change in the expression of the apoptotic inducer Bax was detected. Fas and FADD were significantly elevated in all paced ventricles, and Fas-L was only detected in the paced hearts. Both caspase-2 and caspase-3 were elevated following ventricular pacing.

CONCLUSIONS

We have identified components of the signalling pathways along which apoptosis proceeds following the induction of heart failure in dogs. Apoptosis was also detected in the atria raising the possibility that, like human dilated cardiomyopathy, the molecular changes are global.

MHC recognition in thymic development: distinct, parallel pathways for survival and lineage commitment

The molecular events triggered by MHC recognition and how they lead to the emergence of mature CD4 and CD8 lineage thymocytes are not yet understood. To address these questions, we have examined what signals are necessary to drive the development of CD8 lineage thymocytes in TCRalpha(-) mice in which TCR/MHC engagement cannot occur. We find that the combination of constitutive Notch activity and constitutive Bcl-2 expression are necessary and sufficient to allow the appearance of mature CD8 lineage thymocytes in TCRalpha(-) mice. In addition, Notch activity alone in TCRalpha(-) mice can induce the up-regulation of HES1, suggesting that thymocytes are competent to respond to Notch signaling in the absence of MHC recognition. These data indicate that survival and lineage commitment represent distinct, parallel pathways that occur as a consequence of MHC recognition, both of which are necessary for the development of mature CD8 lineage T cells.

Birth defects after maternal exposure to corticosteroids: prospective cohort study and meta-analysis of epidemiological studies

BACKGROUND

Corticosteroids are first-line drugs for the treatment of a variety of conditions in women of childbearing age. Information regarding human pregnancy outcome with corticosteroids is limited.

METHODS

We collected prospectively and followed up 184 women exposed to prednisone in pregnancy and 188 pregnant women who were counseled by Motherisk for nonteratogenic exposure. The primary outcome was the rate of major birth defects. A meta-analysis of all epidemiological studies was conducted. The Mantel-Haenszel summary odds ratio was calculated for the pooled studies with 95% confidence intervals. A cumulative summary odds ratio was also calculated by combining studies in chronological order. Chi-squared for homogeneity was determined to establish the comparability of the studies.

RESULTS

In our prospective study, there was no statistical difference in the rate of major anomalies between the corticosteroid-exposed and control groups. In the meta-analysis, the Mantel-Haenszel summary odds ratio for major malformations with all cohort studies was 1.45 [95% CI 0.80, 2.60] and 3.03 [95% CI 1.08, 8. 54] when Heinonen et al. ('77) was removed. This suggests a marginally increased risk of major malformations after first-trimester exposure to corticosteroids. In addition, summary odds ratio for case-control studies examining oral clefts was significant (3.35 [95% CI 1.97, 5.69]).

CONCLUSIONS

Although prednisone does not represent a major teratogenic risk in humans at therapeutic doses, it does increase by an order of 3.4-fold the risk of oral cleft, which is consistent with the existing animal studies.

Treatment with cytotoxic immunosuppression agents increases urinary excretion of JCV in patients with autoimmune disease

Human JC virus is ubiquitous in human populations and is reactivated frequently in immunosuppressed patients. Fifty-one patients with autoimmune disease receiving immunomodulating therapy were evaluated to study the possible relationship between immunosuppression and JCV viruria. Patients were divided into cytotoxic and noncytotoxic treatment groups based on their prescription. The incidence of JCV viruria in the cytotoxic treatment group was significantly higher than that in the noncytotoxic group (67% vs. 28%; P < 0.05). Most patients with JCV viruria were receiving corticosteroid (P = 0.03 for any dose and P < 0.001 for higher-dose treatments) and cytotoxic agents (P = 0.02). Age, disease duration, and medication duration appeared not to be the precipitating factors of JCV viruria in this study. The results of clinical evaluation indicate that cytotoxic immunosuppression may play an important role in JC virus reactivation.

Portal hypertensive gastropathy: radiographic findings in eight patients

OBJECTIVE

The purpose of our study was to determine the findings of portal hypertensive gastropathy on barium studies in eight patients and whether there are useful radiographic criteria for diagnosing this condition.

CONCLUSION

Our experience suggests that portal hypertensive gastropathy may manifest on barium studies as thickened nodular folds in the gastric fundus. Although varices or various forms of gastritis can also produce thickened gastric folds, portal hypertensive gastropathy should be suspected when this finding is detected in patients with known portal hypertension.